Ur-Nammu was one of the most prominent rules of Sumer. Ur-Nammu began his career as a governor to the king, Utukhegal. Utukhegal proved to not be ambitious and was usurped by Ur-Nammu around 2112 B.C.
The kingship of Ur-Nammu founded the Third Dynasty of Ur. He ruled for about 17 years and during this time he was determined to bring Ur back to prominence. In Ur he constructed the great Ziggurat which stood 60' high and had a base of 200'. He built and restored temples in Ur, as well as the other cities of Sumer. He also dug many canals helping the agriculture of the cities to grow.
Ur-Nammu is also famous for a series of laws or "code" which he enacted. While the laws are usually credited to Ur-Nammu there is some thought they were written by his son, Shulgi. The laws were placed to protect the weak and poor against the rich and powerful, including provisions for canceling debts which the poor could not possibly repay.
Ur-Nammu died about 2095 in battle with the Gutians, but his memory lived on for several centuries in Ur.